So… much… STUFF!

Gods, this is what I’m faced with all the time. Someone needs to tell me how proper science bloggers pick articles to discuss, because I just get my RSS alerts, start squeeing, and end up not writing about anything because damn, I WANT TO WRITE ABOUT EVERYTHING!

I give up. I’ll just dump all the cool stuff that’s accumulated on my desktop and bookmark bar here and return to lengthy meandering whenever I don’t feel like I’ve been caught in a bloody tornado 😉

So, here is some Cool Stuff…

(1) A group measured the rate of DNA decay in 158 moa bones of known age from three sites. Really cool stuff, to go out and directly measure how ancient DNA disappears from dead things under more or less identical conditions. The unsurprising result is that DNA decays exponentially, a bit like radioactive material. This suggests that the main cause of the decay is random breaking of the strands. The surprising bit is that this happens much more slowly than previously estimated, suggesting that in ideal (read: frozen) conditions, it might be worth looking for preserved DNA in samples as old as a million years.

(On a side note, if you ever get a chance to see a talk by Eske Willerslev, one of the authors and a leading expert on ancient DNA, don’t miss it. The man is absolutely hilarious.)

– Allentoft ME et al. (2012) The half-life of DNA in bone: measuring decay kinetics in 158 dated fossils. Proceedings of the Royal Society B FirstCite article, available online 10/10/2012, doi: 10.1098/rspb.2012.1745

(2) The beaks of the finches, or mixing and matching developmental recipes. This study examines the genetic basis of beak shape in three little birds closely related to Darwin’s famous finches. The three finches, just like Darwin’s, share the same basic beak shape, only bigger or smaller. However, there seem to be two distinct developmental programs at work, using different genes and parts of the skeleton to orchestrate beak development. One of the three newly investigated species (the one most closely related to Darwin’s finches) apparently uses the same developmental program as its more famous relatives, even though its beak is shaped more like the other two birds studied here. I told you – genetics, development and homology are complicated 😉

– Mallarino R et al. (2012) Closely related bird species demonstrate flexibility between beak morphology and underlying developmental programs. PNAS 109:16222–16227

(3) Armoured fossil links worm-like molluscs to chitons. There’s a little-known group (or groups) of molluscs called aplacophorans that have only a coat of tiny spicules instead of shells and look more like worms than “proper” molluscs. Exactly where they fit into our picture of mollusc evolution has been controversial to say the least – they could represent an old lineage separate from other molluscs, they could be related to cephalopods, they could be related to chitons, they could be one group or they could be two lineages in completely different places on the tree… Well, a new fossil named Kulindroplax seems to argue for the chiton connection: the animal has the characteristic armour plates of a chiton on an aplacophoran-like body. Similar creatures have been discovered before, but this guy with its detailed 3D preservation provides the clearest evidence of the link so far.

– Sutton MD et al. (2012) A Silurian armoured aplacophoran and implications for molluscan phylogeny. Nature 490:94-97

(4) More cool fossils – this time straight from my beloved Cambrian. Nereocaris, a newly described Burgess Shale arthropod, suggests to its discoverers that the earliest arthropods weren’t predators prowling the seafloor, but swimmers who might have been filter feeders and certainly weren’t predators. The animal has a bivalved shell around its front end, similar to many other Cambrian swimming arthropods, and a long abdomen with paddles at the end. It bears the arthropod hallmark of a hardened and jointed exoskeleton, but it lacks specialised limbs such as antennae or mouthparts. In a cladistic analysis of arthropods and their nearest relatives, the new species comes out on the first branch within true arthropods, and the next few branches as we move towards living arthropods all contain similar shelled, swimming creatures. Since the non-arthropods closest to the real thing (i.e. anomalocaridids) were also fin-tailed swimmers, this arrangement makes the transition between them and true arthropods smoother than previously thought. It also suggests that the hard exoskeleton so characteristic of arthropods originally functioned in swimming – perhaps as an anchor for swimming muscles.

– Legg DA et al. (2012) Cambrian bivalved arthropod reveals origin of arthrodization. Proceedings of the Royal Society B FirstCite article, available online 10/10/2012, doi: 10.1098/rspb.2012.1958

*

And … there was also

… but it’s almost bedtime, and if I wanted to summarise every one of those, I’d be here all weekend 😦

See, this is why being a science nerd today is both amazing and frustrating. There’s just so. Much. Stuff.

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